Apparatus for Precise Temperature Brightness Compensation of LED

Abstract

The disclosed invention teaches a circuit which employs a constant voltage power source and series resistance to power an LED or LED assembly so that the brightness of the LED will be the same throughout its expected operating temperature range, solving the problems of temperature brightness compensation of a LED using an inexpensive power supply and simple design.

Description

RELATION TO OTHER PATENT APPLICATION

[0001] This application hereby incorporates by reference the specification, oath, and drawings from application Ser. No. 14/451,435, from which this present application is a continuation. No new matter is included in this application.

[0002] Inventorship is this patent application is unchanged from Ser. No. 14/451,435, so no new oath is necessary.

[0003] In application Ser. No. 14/451,435, an office action dated Feb. 26, 2016 issued an election requirement to select from three species of claims, leading to the inventor's decision to select Species I, directed to the a set of method claims and consisting of claims 1-3 and 20-28. The USPTO issued a Notice of Allowance regarding claims 20-28 on Jul. 11, 2016, after an interview and examiner's amendment as detailed that same day.

[0004] This application continues application Ser. No. 14/451,435 with claims 4-17, defined as Species II in the aforementioned 2/26/2016 office action, renumbered as 1-14 in this application.

Claims

1. A drive circuit to operate an LED assembly, comprising: a. A primary power supply; b. A voltage stabilizer; c. An LED as a temperature sensor; d. An external resistor; e. Said voltage stabilizer including an output voltage equal to a optimal voltage specified as reported by LED specifications or otherwise calculated; f. Said voltage stabilizer has internal resistance far less than the optimal resistance as reported by LED specifications or otherwise calculated; g. Said external resistor has resistance equal to optimal resistance, as reported by LED specifications or otherwise calculated.

2. The LED drive apparatus of claim 1, with an additional element of a voltage stabilizer, with input, output, and ground package terminals; the input terminal of said voltage stabilizer is connected to the primary power supply; the ground terminal of said voltage stabilizer is connected to the ground; the output terminal of said voltage stabilizer is connected to first terminal of the LED assembly; the second terminal of the LED assembly is connected to the first terminal of the external resistor; the second terminal said of the external resistor is connected to the ground.

3. The LED drive apparatus of claim 2, wherein the internal resistance of said voltage stabilizer equals the said optimal resistance and said external resistor is absent.

4. The LED drive apparatus of claim 3, wherein said missing external resistor is replaced with a current mirror.

5. The LED drive apparatus of claim 2, wherein resistance of the external resistor is equal to the optimal resistance minus internal resistance of the voltage stabilizer.

6. The LED drive apparatus of claim 4, wherein voltage on the external resistor or output current of the current mirror is used for protection system.

7. The LED drive apparatus of claim 2, wherein said voltage stabilizer is an analogous circuit.

8. The LED drive apparatus of claim 2, wherein the voltage stabilizer is a switching regulator.

9. The LED drive apparatus of claim 2, wherein the voltage stabilizer includes a current limiter or current protection device.

10. The LED drive apparatus of claim 2 in which the drive apparatus is driving multiple LEDs, wherein the optimal voltage of said voltage stabilizer equals the optimal voltage of a single LED multiplied by number LED in the assembly.

11. The LED drive apparatus of claim 2 in which the drive apparatus is driving multiple LEDs, wherein the optimal resistance equals said optimal resistance of a single LED multiplied by number of LEDs in the assembly.

12. The driving apparatus of claim 2, wherein the output terminal of the voltage stabilizer is connected to a first terminal of an in-parallel LED assembly and other terminals of every assembly of LEDs is connected to terminals of external resistors and all other terminals said of external resistors connect to ground.

13. The driving apparatus of claim 12, wherein said voltage stabilizer has an output voltage equal to the optimal voltage of one LED assembly and has an internal resistance substantially smaller than the optimal resistance divided in the parallel branches, and said external resistors have a resistance equal to the optimal resistance of one LED assembly.

14. The LED drive apparatus of claim 12, wherein said resistance of external resistors is equal to the optimal resistance of an LED assembly minus the internal resistance of said voltage stabilizer multiplied by number of parallel branches.

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